Examine source code of Pacer speed reading

{
  "manifest_version": 2,
  "name": "Pacer speed reading",
  "short_name": "Pacer",
  "version": "0.1.0",
  "description": "An assistant to help you boost your reading speed!",
  "icons": {
    "48": "icons/logo_48x48.png",
    "128": "icons/logo_128x128.png",
    "256": "icons/logo_256x256.png"
  },
  "permissions": [
    "activeTab",
    "storage"
  ],
  "browser_action": {
    "default_icon": "icons/logo_48x48.png",
    "default_title": "Pacer",
    "default_popup": "popup/index.html"
  },
  "content_scripts": [
    {
      "matches": [
        "<all_urls>"
      ],
      "js": [
        "content/script.js"
      ]
    }
  ],
  "browser_specific_settings": {
    "gecko": {
      "id": "pacer@example.com"
    }
  }
}